Mother-to-child transmission of HIV (MTCT)

Mother-to-child transmission (MTCT) of HIV is one of the major causes of HIV infection in children. It is estimated that about 600 000 children are infected in this way each year (this figure accounts for 90% of HIV infection in children). Unless preventive measures are taken (such as Nevirapine for mother and baby), up to 40% of children born to HIV-positive women are infected.

HIV can be transmitted from an infected mother to her baby either

• Via the placenta during pregnancy,
  
• Through blood contamination during childbirth, or
  
• Through breastfeeding.
  

Why are only some babies of HIV+ women infected and others not?
The transmission of HIV from a mother to her baby depends on many factors, such as the viral load in the mother's blood at the time of pregnancy (or breastfeeding).

Viral load is very high (and the CD4 count low) shortly after infection (during the acute phase) and again in the final stage of AIDS.

A pregnant woman is more likely to transmit the virus to her foetus during pregnancy if she becomes infected just before or during pregnancy (when she is in the acute phase), or if she has Aids (final stage).

The viral load in breastmilk is also higher in these phases. HIV can also transmit easier to a baby through breastfeeding if the mother's nipples are cracked, or if the baby has oral thrush.

HIV-infected pregnant women should always use condoms to prevent re-infection. Any new HIV infection during pregnancy (or while breastfeeding) is likely to result in an increase in the viral load, and this will increase the likelihood of MTCT. Re-infection may also cause the mother's disease to progress more rapidly, leaving the child orphaned sooner.

Should an HIV+ woman breastfeed her baby?

There is no easy answer to this question. The breastfeeding versus bottle-feeding debate in Africa revolves around very complex issues, such as the following:

• Formula milk may not be readily available in poor communities
  
• Mothers may not have access to clean and safe water supplies wherewith to prepare the feed
  
• Mothers may not know how to sterilise bottles
  
• Mothers may not know how to prepare the formula milk (i.e. what the correct powder-to-water ratio should be)
  
• Mothers may be ignorant of the fact that they should use clean, boiled and cooled water for formula feeding
  
• Some mothers may also not know that they will compromise the baby's health if they add more water (increase the water in the water-powder ratio) in an attempt to save money, or to feed other children